In recent years, many countries have been experiencing a strong tendency to become tourist-oriented countries. Becoming a tourist-oriented country is an important issue from the point of view of encouraging the revival of a nation as well as invigoration of local communities and the tourist industry could become one major industry in each country.
To achieve this, development of infrastructures for tourist areas as well as improvement of services provided to tourists become very important too.
Development of infrastructures may include for instance addition/development of access to tourist areas as well as addition/development of amenities for tourist areas.
On the one hand, improvement of services may include advertising of tourist areas to the people who live in other areas, wide distribution of tourist guides as well as maps to tourists in tourist areas, as well as wide distribution/diffusion of guide information with respect to suggestions for recommended tours for sightseeing a plurality of spots in a tourist area, and with respect to various target objects in the tourist area specifically sightseeing resources (for instance, establishments, buildings, exhibits, cityscape, land forms (mountains, sea, rivers, lakes, straits, valleys, plains, harbors, etc.), animal life, vegetable life, historical sites, places of scenic beauty, traditional arts, folklore, events, etc.) which are specific to that area.
Thus, wide diffusion of geographical information with respect to tourist areas, historical/scientific information with respect to the respective target objects within the tourist areas, information regarding tourist routes as well as information on tourist valuation of such tourist areas (hereinafter collectively referred to as “tourist information”) becomes very important in revitalizing tourist industry. The tourist information is provided to the tourists in the form of text, image (still image, video picture) or voice, etc.
On the other hand, thanks to the rapid progress of information and communication technology, it is common sense for tourists to travel while carrying a communications device capable of communication with the outside. Such communications devices are also referred to as user portable terminals and are classified into portable telephones, smart phones, PDAs, tablet PCs, etc. Also, it is very common for this type of communications devices to have a built-in camera function or a positioning function (for instance, GPS function, etc., location measurement function, azimuth angle measurement function, attitude measurement function).
Thus, in recent years, the use of user portable terminals has made it possible for tourists to receive useful tourist information from the outside as needed, while sightseeing.
Nevertheless, the amount of tourist information which can be accessed by a tourist using a user portable terminal is enormous. Thus, when the tourist has to retrieve tourist information by selecting a retrieve key himself/herself and entering the information in the user portable terminal by himself/herself, the retrieval operation takes time and effort and is therefore inconvenient. Furthermore, selection of an incorrect retrieval key can make it impossible to retrieve the appropriate tourist information.
Thus, in order to provide an improved user portable device which is easy to use by a user, in this case a tourist, it is necessary to develop a technology for retrieving local tourist information suitable for the current tourist area, which is either completely or partially automatic, by eliminating the user's involvement as much as possible.
In this context, a variety of technologies have already been proposed for automatic retrieval of local tourist information suitable for a tourist's current location. These retrieval technologies are classified into location-based retrieval method, vision-based retrieval method and a hybrid retrieval method incorporating the first two methods (for instance, refer to Patent Literature 1).
According to the location-based retrieval method, a tourist's current location is first measured and then retrieval of tourist information is carried out based on the current location as measured. More specifically, a tourist area which satisfies the conditions relating to the distance to the current location as measured is extracted from a plurality of candidate tourist areas and presumed to be the current tourist area for the tourist. Then, the tourist information which was correlated in advance with the extracted tourist area is provided to the tourist as the most suitable tourist information.
On the other hand, according to the vision-based retrieval method, the target object onto which the tourist is currently focusing is recognized spatially and retrieval of tourist information is carried out based on a three dimensional shape of the target object thus recognized. More specifically, a target object having a three dimensional shape which is identical with the three dimensional shape of the target object which was recognized spatially is extracted from the plurality of candidate target objects and is presumed to be the current target object for the tourist. Then, the tourist information which was correlated in advance with the extracted target object is provided to the tourist as the most suitable tourist information.    [Patent Literature 1] Japanese Patent Application Laid Open No. 2003-150616